Field of the Invention
The present invention relates to a bipolar plate-electrode assembly used for a unit cell for a redox flow battery and more particularly, to a bipolar plate-electrode assembly using a thermoplastic resin and a manufacturing method thereof.
Description of the Related Art
A redox flow battery is one of core products closely related to renewable energy, reduction in greenhouse gas, rechargeable batteries, and smart grids, which have been attracting the greatest attention in the world in recent years. A fuel battery is a product which is expanding rapidly in the market in the world as a renewable energy source to replace fossil fuels without emission of pollutants. Currently, most of the energy is derived from fossil fuels, but there is a problem in that the use of such fossil fuels has serious adverse environmental impacts such as air pollution, acid rain and global warming, and low energy efficiency.
In recent years, in order to solve the problems caused by the use of such fossil fuels, interest in renewable energy and fuel cells has rapidly increased. Interests and research on such renewable energy are being actively performed not only in domestic but also worldwide.
Although the renewable energy market has entered the maturity stage both domestically and internationally, there is a problem that the amount of energy generated due to environmental influences such as time and weather is greatly changed due to the nature of renewable energy. As a result, the spread of an energy storage system (ESS) for storing regeneration energy generated for stabilization of renewable energy generation is very required, and the redox flow battery is attracting attention as such a large-capacity energy storage system.
A general structure of the redox flow battery to which the present invention is applied is configured by a stack 1 with stacked cells in which an electrochemical reaction occurs, a tank 3 for storing an electrolyte, and a pump 4 for supplying an electrolyte to the stack from the electrolyte tank.
FIG. 2 shows a simplified structure of the stack 1 to which the present invention is applied and shows an endplate 11, an insulating plate 12, a current plate 13, a bipolar plate 14, a gasket 15, a flow frame 16, an electrode 17, a gasket 15, an ion-exchange membrane 18, a gasket 15, an electrode 17, a flow frame 16, a gasket 15, a bipolar plate 14, a current plate 13, an insulating plate 12, and an endplate 11 from the left side. A unit cell is formed from the bipolar plate 14 to the bipolar plate 14, and generally, one stack is configured by stacking tens to hundreds of unit cells.
The present invention intends to manufacture an assembly for integrating a bipolar plate 14 and electrodes 17 disposed at both sides of the bipolar plate 14, and in this connection, there is U.S. Pat. No. 6,656,639 B1.
However, in U.S. Pat. No. 6,656,639 B1, since the assembly is manufactured by putting an electrode and a resin sheet (bipolar plate material) in a jig and thermally compressing them, the resin sheet at a portion which is not in contact with the electrode, is heated and at the boundary between a portion not in contact with the electrode and a portion in contact with the electrode a residual stress is generated during a cooling process, and as a result, there is a problem in that the bipolar plate is deformed or the strength thereof is weakened when the jig is separated.